Boiler-furnace



(Nb Model.) 2 sheetssheet 1. R. H. LAIRD.

l BOILER PURNAGB.

' No. 540,393. Patented June 4, 1895.

( No Modell.) Y 2 sheetssheet 2.

R. H. LAIRD.Y BOILER FURNAGE.

No. 540,393. Patented June 4, 1895.

UNrrn rares arnN'I @einem ROBERT II. LAIRD, or cI-IIcAcO, ILLINOIS.

SPECIFICATION forming part of Letters Patent No. 540,393, dated June 4, 1895.

Application filed J'uly 3,1894. Serial No. 516,476. (No model.)

To all whom t may concern:

Be it known that I, ROBERT H. LAIRD, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a new and useful Improvement in Boiler-Furnaces, of which the following is a specification.

My invention relates to improvements in water heaters generally, though more particularly to improvements in boiler furnaces ofthe class designed more especially for generating steam in large quantities andat high pressure; and my object in the latter connection is to improve the construction of such boiler furnaces to the end of giving to the boiler comparatively great capacity for steam generation, and so utilizing the heat from the furnace that particular economy will result in the amount of fuel necessary for the generation of a given quantity of steam.

In the drawings, which illustrate a locomotive furnace and boiler constructed in accordance with my improvements, Figure l is a broken vertical and longitudinal section on line l of Fig. 2, and Fig. 2 a broken section on lines 2 2 of Fig. 1.

A is an upper retort or coking chamber provided With a feed door` A and a dumping grate A2. B is a lower combustion chamber `provided with a` door B' and a grate B2; and C an ash pit. Extending over the top, sides and back of the combustion and coking chambers is a chamberror water jacket D. Extending over the top and sides of the Water jacket D is a chamber or flue E; and over the front, sides and top of the chamber or flue E is a chamber F more highly arched than the other chambers to afford a steam space X, and surmounted by a steamdomeX. In the chamber E are fines E extending from the ash pit C to the level of the top of the lower combustion chamber B, whence they pass through the water jacket D to the chamber B just below the upper grate bars A2. Just above the lower grate bars B2 are flues E2 which ex-v tend between the combustion chamber B and chamber E through the water jacket. Extending between the water jacket or charnber D and chamber F, a little above the plane of the lower grate bars B2 are circulating tlucs tt; and circulating flues t extend between the chambers D and F, through the chamber' is a hollow diaphragm H containing a water chamber F which communicates at its upper side with the chamber F.

I is the rear tube-sheet of the boiler, and l the front tube-sheet, between which extend three series of dues s, s and s2, respectively. The tubes of the lower series s are comparatively large, say four inches in diameter. The tubes of the central series s are preferably somewhat smaller, say three inches in diameter; and the tubes of the top series s may be still smaller, say two and one-half inches indiameter.

In front of the tube-sheet I is a lower smokebox or chamber G to which extend the flues ss, and above the chamber G', and divided from the latter bya diaphragm r, is an upper smokebox or chamber G2 to which extend the iiues s2 only. At the base ot' the chamber H is an opening q provided with a damper q. Around the sides and lower part of the chamber H is a water jacket D, which at one end, opens into the water jacket D, and at its Opposite end into the boiler. The opening q extends through the water jacket. Between the diaphragm H andtube-sheet I is a damper p, at about `the plane of the lower end of the diaphragm, and the plane of division between the series,s and s', of tubes. Thesmoke-box G2 communicates with the smoke-stack. Not

shown.

Extending across the chambers F E to the chamber or water jacket D is a feed pipe Y.

The pipe Y may be the feed pipe for the boiler and extends from the water-tank, on the locomotive tender; a suitable injector being interposed in the pipe. The water jackets D and F and t'he boiler are filled and maintained filled with water up to the waterline a, which is above the tops of the chamber E and boiler tubes s2. Initially, the fire is built upon the grate bars B2, and when the combustion chambers become heated to a high degree all further feeding of fuel is done through the upper IOC door A', the fuel beingspread upon the upper entirely consumed, or lose their incandescence grates A2 and coked before it is dumped upon the lower grate. l

The upper chamber is not only a preparatory chamber for heating the fuel before it is introduced into the lower combustion chamber, but it is a retort chamber into which no air is admitted to support combustion, so that the heat from the lower chamber distills gas from the coal on the upper grate, the gas of distillation passing through the upper grate bars to the chamber B. The fuel therefore that is dumped upon the lower grate is more or less coked.

In practice air to supply combustion enters A which pass down through the fuel on the grate A2 to the chamber B. The gases as they l descend into the chamber B and are carried down by the air current from the flues E are subjected to the heat in the latter chamber,

whereby substantially complete lcombustion g of the gases is effected. From the chamber B the products of combustion pass through the fines E2 to the chamber E and pass thence to the combustion chamber Il.

in the diaphragm chamberF and in the water jacket D; and, in passing through the tubes 3,'

returning through the tubes s', and passing again through the tubes s2, approximately lall the heat of the products of combustion is absorbed and utilized in heating the surround` As the water in the chamber D` ing water. is heated it rises through the tlues t', water from the chamber F entering the chamber D j through the iiues t, whereby continued circulation is kept up.

The products of combustion in passingfrom the chamber H through the lower tubes s lose v a` certain proportion of their lieatand become y contracted in volume, and they are `still further contracted in passing through the second p Therefore by providing tubes s' of .proportionately smaller diameter than the tubes s and tubes 'S2 of still smaller diameter, an even draf t is maintainedthrough the flues. Live cinders which are light enough to be carried through the tubes by the draft` series of tubes s.

will, owing to the distance of their travel be The diaphrag-m H deliects the products of combustion i downward and cause them to pass below the 5 damper p, and through the lower series s of tubes to the smoke-box G', whence they pass t through the return tubes s to the part H2 of the chamber H, and thence `through the tubes s2 to the smoke-box G2 andout at the smoke- 'st-ack. The heat of the combustion chambers exerts itself directly upon vthe water in the@ chamber D, and the heat of the hot products of combustion passing through the chamber E is exerted against the lchambers D and F. In passing to the chamber H the products of" combustion exert their heat upon the outerr surface of the water jacket D; upon the water before reaching' the chimney.

In my improved construction substantially all the available heating space is utilized in making steam, and as all the walls with which the products of combustion come into contact are surrounded by water, the danger of injury t0 the metal, forming the walls, from the heat is reduced to the minimum. By feeding the furnace at the upper chamber the cooling influence of fresh fuel upon the main re bed B2 is avoided; and in the down draft of the more volatile gases substantially perfect combustion of the fuel is attained.

At suitable places, as at the base of the chamber F on opposite sides, and at the base of the chamber F', draw-olf cocks may be provided for draining out sediment when desired. The dran/off cocks may be of any suitable form usually provided for this purpose on other boilers.

Though my invention, as illustrated, is intended for use in connection with boiler-furnaces adapted to generate 'steam at high pressure, it may be employed in connection with steam-heating systems, whe-re steam is generated at low pressure, or in connection with hot-water heating syste-ms. In either case the structure is adapted to economize in fuel by utilizing the heat therefrom to an extent beyond the capacity of furnaces hitherto constructed for the same purpose.

While I prefer to construct my irnprove ments as shown and described, they may be modified in the matter of details without departing from Athe spirit of my invention as delined by the claims.

Vthat I claim as new, and desire to secure by Letters Patent, is-

l. In a boiler furnace, the combination of a combustion chamber B provided at its lower side with a grate B2, an inner, water-jacket D extending -over the top and sides of the chamber B, la Hue chamber E extending over the -top and sides of the inner water-jacket, out- 'the said outer and linner water-jackets to` ward the lower and upper parts of the latter,

'all constructed and arranged to operate substantially as described.

2. Ina boiler-furnace, the combination with the c0mbustion-chamber of a chamber H, a flue extending from the combustion chamber to the chamber I'I, a chamber H2, a separating wall between the chambers H and H2, chambers G and G2, a dividing-wall between the 'chambers G fand G2, a boiler extending between the chambers H H2 and the chambers G G2, provided with a lower series of tubes s extending between the chambers H and G', an

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intermediate series of return tubes s', of smaller diameter than the tubes s, extending between the chambers G' andH2, and an upper series of tubes s2 of smaller diameter than the tubes s', extending between the chambers H2 and G2, substantially as described.

3. In a heater or boiler-furnace, the combination of a combustion chamber, an inner water-jacket D extending over said chamber, a flue E extending from said chamber around the inner water-jacket, a chamber H with which the fine E communicates, a boiler G, having tubes extending between the chamber H and a chamber G', between the chamber G and a chamber H2 and between the chamber H2 and a chamber G2, an outer Water-jacket extending over the fine E and chambers H H2 and communicating with the boiler G, and circulating conduits between the inner and outer water-jackets, substantially as described.

4. In a heater or boiler-furnace, the combination of an nppercoking chamber A having a feed door, a lower combustion chamber B, a dumping-grate between said chambers, an inner waterjacket D extending over said chambers, a iiue E extending from the said lower chamber around the inner water-jacket, a chamber H to which the flue E extends, a boiler, G, having tubes s, extending from the chamber H to a chamber G', tubes s' extending from the chamber G' to achamber H2, and tubes s2 extending from the chamber H2 to a chamber G2, an outer water-jacket extending over the tlue E and chambers H H2 and communicating with the boiler G, a hollow diaphragm H', having a Water chamber F', between the chambers H and H2, and circulating conduits between the inner and outer water-jackets, substantially as described..

ROBERT H. LAIRD. 

